api/views/mapitems: Fix "AirspaceSchema" instance
api/views/mapitems: Fix "AirspaceSchema" instance

Harry-R/skylines,shadowoneau/skylines,shadowoneau/skylines,RBE-Avionik/skylines,skylines-project/skylines,skylines-project/skylines,Harry-R/skylines,skylines-project/skylines,Turbo87/skylines,RBE-Avionik/skylines,shadowoneau/skylines,skylines-project/skylines,RBE-Avionik/skylines,Turbo87/skylines,Harry-R/skylines,Turbo87/skylines,Harry-R/skylines,shadowoneau/skylines,RBE-Avionik/skylines,Turbo87/skylines